Many typical “rack mount” computer systems rely on “hot” swappable power supplies. In particular these hot swappable power supplies are designed to be pulled out and replaced as the system is running. Further, in such rack mount systems, several modular power supplies may be grouped together to power an individual system or subsystem within the rack. Accordingly, should one or more of the modular power supplies fail, the full amount of power available to specific systems that are powered, either singly or as tied together in a group, is diminished.
In some cases the indication of such a power problem is noticed only through the failure of the specific system due to lack of power. If the system is composed itself of several sub-systems or boards, a controller may selectively depower some of the sub-systems on boards based on available power in order to avoid a condition where more power is demanded than is available. Such strategies lead to inefficiencies in the operation of rack-mounted systems. In many applications, the depowered sub-systems on boards may be central to continued successful operation of an endeavor, and the inefficient operation of the system can lead to substantial problems in the endeavor that is being pursued.